Reuben Dise and Matthew Aasted

June 23, 2010

Overview

Darwin Thinner

Autonomy

OverviewResearch Overview

Darwin Thinner

Autonomy

% Variable Production Costs (TFPG, 2010)

Labor57%

Other43%

Peaches

Labor59%

Other41%

Apple

Labor68%

Other32%Sweet

Cherries

• Labor Intensive

– 31% of cling peach

cultural costs

• Chemical Thinning

– Limited uses, especially

in Stone Fruit and

Organic Production

• Mechanization is being

adopted by growers.

(Schupp et al., 2008, Baugher et al., 2009)

• Net Economic Impact

– CA = $1490/acre

– PA = $934/acre

– WA = $847/acre

– SC = $264/acre

Blossom Thinned with String Thinner

Hand Thinned

(Baugher et al., 2010)

• Improve Actuation

• Improve Control

• Add Sensing and

Autonomy

• Increase speed

Overview

Darwin Thinner

Description Modifications Testing

Autonomy

Rotating

Spindle

Hydraulic

Motor

3 pt

Mounting

Speed

Controller

Hydraulic Angle

Adjustment

Chords

Flow Control

Valve

Thinner Moved to Rear

35 degree Tilt

(unchanged)610 mm Lateral

Offset Added

Spindle

Rotation

Remains

Unchanged

Proportional

Control

Valves

Flow

Divider

Position Sensors

(Potentiometers)

Joystick for

Tilt and Offset

E- Stop

Autonomy

Controls

LED Indicator

Lights

• Manually Actuated

Darwin (walk behind)

• Fixed angle

Darwin, moved in and out

of canopy by steering

tractor

• Hand Thinned Control

a

a

a

b a b

c b c0

10

20

30

40

50

60

Upper Lower Scaffold

% B

los

so

ms

Th

inn

ed

Manually Actuated Fixed Control

a

a

a

ab

a

b c b0

10

20

30

40

50

60

70

80

Upper Lower Scaffold

% B

los

so

ms

Th

inn

ed

Manually Actuated Fixed Control

* Letters Represent Statistically Different Groups at alpha = 0.05

a

a

a

a

a

a

a

a

a a

a

a

b

b

b b

b

c

0

5

10

15

20

25

30

35

#/ c

m^

2 L

CS

A

Manually Actuated Fixed Control

a

a

aa

a

a

b

a

a b

a

b

c

b

b

b

b

c

0

5

10

15

20

25

30

35

#/ c

m^

2 L

CS

A

Manually Actuated Fixed Control

* Letters Represent Statistically Different Groups at alpha = 0.05

a

a

b

0

20

40

60

80

100

120

140

160

Manually Actuated

Fixed Control

Ma

nh

ou

rs/a

cre

a

a

b

0

10

20

30

40

50

60

70

80

90

100

Manually Actuated

Fixed Control

Ma

nh

ou

rs/a

cre

* Letters Represent Statistically Different Groups at alpha = 0.05

Overview

Darwin Thinner

Autonomy Sensing TestingFuture Work

Speed Sensor

Distance Sensors

Distance and Mapping

Calculations

Tree Map

Autonomous Positioning

Ultrasonic

Sensor

Mast Position

Feedback

Sensors

GPS

Computer and

Microcontroller

Laser

Rangefinder

• Arduino Microcontroller

– $65

• 4 Sonar Range Finders

– Maxbotix LV-MaxSonar-

WR1

– $100

• Low Cost GPS

– USGlobalSat EM-406A

GPS Module

– $60

Sensor

Mast

z

y

x

Best Fit

Line

Orchard

Row

Sensor Distance

Readings (dashed lines)

• Trimble AG GPS 442

• SICK LMS 120 Laser

Rangefinder

• Linear Least Squares

Regression

• Collision Search in a

Voxel Grid

• Angle is less expensive

because it is faster

• Fully extended and angled

out is preferred

• Further Develop

Autonomy Algorithms

• Compare:

– Manually Controlled

(baseline)

– Ultrasonic Sensing

– Laser Sensing• Next step is a

selective thinner

Overview Research Overview

Darwin Thinner

Description Modifications Testing

Autonomy Sensing Testing Future Work

Advisor: Dr. Paul Heinemann, PSU ABE

Committee Members:

Dr. Jude Liu, PSU ABE

Dr. Jim Schupp, PSU FREC

Dr. Tara Baugher, PSU Adams Co. Ext.

Dr. Ben Grocholsky, CMU Robotics Institute

Co-researcher: Matt Aasted, CMU Robotics Institute

Special Thanks To:

Jim Schupp

Edwin Winzeler

Tom Kon

Celine Kuntz

Russell Rohrbaugh

Amelia Jarvinen

Terry Saluda

Research Sponsored by:

USDA SCRI

Assistantship Support by:

California Canning Peach Association